Does the magnet test tell you if gold is real?
A magnet separates solid gold and silver from pieces with an iron or steel base, because neither precious metal is magnetic. It cannot tell you whether a piece is well made, and it cannot catch the most common problem base metal of all: brass is not magnetic either, so brass-based plated jewelry passes the test.
By SIAFRA
The magnet test answers one question: is this solid precious metal, or is there something ferrous under the color. Gold and silver are not magnetic, so a piece that pulls hard toward a magnet has a base metal inside it. What the test cannot do is tell you which base metal, and that is the part that decides whether the piece marks your skin.
It is the most repeated at-home test there is, usually described the way one jeweller puts it: “Gold and silver are not magnetic. When a piece is gold-plated, there’s metal underneath. Hold a strong magnet on your piece of jewelry. If the magnet sticks, this is an immediate indication of a fake material being used.” (Jacqueline’s Fine Jewelry)
The first half of that is physics. The second half is where most people go wrong, in both directions.
What each result actually tells you
| What the magnet does | What it means | What it does not mean |
|---|---|---|
| Pulls hard, sticks and holds | There is a ferrous metal in the piece: iron, carbon steel, a nickel-bearing alloy, or a steel clasp, pin or spring | Not that the piece is badly made. Plated steel is a legitimate construction, openly sold as plating |
| A faint tug, or clings only at an edge | Often a stainless steel component, or a small ferrous part such as an earring post or hinge | Not a verdict on the rest of the piece |
| Nothing at all | No ferrous metal. Consistent with solid gold or silver | Not proof of either. Brass, copper, aluminium, zinc and most jewelry stainless are all non-magnetic too |
The last row is the one that matters, and it is why this test gives false comfort more often than it catches anything. Brass is roughly two thirds copper and it is not magnetic. So a gold-plated brass piece, the exact construction most likely to leave a green mark once the finish thins, sails through the magnet test looking as innocent as solid gold.
Why stainless steel gives an ambiguous answer
Steel is the one case where a weak result means very little. The stainless grades used in jewelry are austenitic, and as Carpenter Technology puts it, “all austenitic stainless steels are paramagnetic (nonmagnetic) in the fully austenitic condition as occurs in well-annealed alloys.”
That changes once the metal is worked. “The permeability increases with cold work due to deformation-induced martensite, a ferromagnetic phase,” the same guide notes, and for common grades “the increase in magnetic permeability can be appreciable, resulting in these grades being weakly ferromagnetic in the heavily cold-worked condition.” (Carpenter Technology on the magnetic properties of stainless steels)
Practically: a steel-based piece may show a slight pull, or none, depending on how it was formed. Neither reading tells you anything about its quality.
What SIAFRA would do on a magnet
Possibly show a faint pull, and that is expected. SIAFRA is specified as 18K gold PVD over stainless steel. It is not solid gold, it has never been described as solid gold, and the steel is the point rather than a compromise: steel carries no copper, which is what green marks are made of.
That is the distinction a magnet cannot draw for you. Between a plated brass piece and a plated steel piece, the magnet is either silent or nearly so, while the difference between them is the one you will notice in a year.
The checks worth doing instead
- Read the material description for a named base metal. Steel, brass, sterling silver, or nothing at all. A listing that names the plating but not what it sits on has told you which one it is.
- Look for a hallmark if the piece is sold as solid precious metal. Stamped fineness is the ordinary evidence for that claim.
- Ask. The FTC’s own advice for ambiguous plating language is to “ask the seller to explain what they mean when they use these terms.” (FTC consumer guide)
A magnet is a thirty second sanity check for one specific lie: solid gold that is not solid gold. For everything else, the product page is the test.
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